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Explore new approaches using EEG, eye movements, and temperature variability to detect delirium in ICU patients and improve outcomes. Study physiological parameters and EEG characteristics to enhance delirium screening accuracy.
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Delirium detection in Intensive Care patients Willemijn van der Kooi Department of Intensive Care Medicine University Medical Center Utrecht, The Netherlands
Disclosures • Orion Pharma: contributed to printing costs of my thesis • NPK design: contributed to printing costs of my thesis
Introduction Delirium prevalence: • 50%-80% for ICU patients • 10-15% for cardiac surgery patients ICU delirium is associated with: • Long term cognitive impairment • Increased hospital and ICU length of stay • Increased mortality * Actor
Introduction Delirium often (71%) missed by ICU physicians1 • questionnaires developed for screening Daily practice • Sensitivity of questionnaire with best performance (Cam-ICU): • 47% in ICU patients2 • 28% in post-operative patients3 • Cognitive screening may not fit well in the culture of the ICU • 1 Van Eijk et al. Crit Care Med 2009;37:1881-5 • 2 Van Eijk et al. Am J RespirCrit Care Med 2011;184:340-4 • 3 Neufeld et al. Br J Anaesth 2013;111:612-8
Introduction New approach: delirium detection using physiological alterations • Ultimate goal: • 2 sensors coupled to a monitor • Monitor shows on a scale the chance of having delirium
Content Three physiological parameters studied: • Temperature variability • Eye movements • Brain activity (EEG) Future perspective
Temperature variability during delirium in ICU patients Van der kooi et al. PLoS One. 2013; 8:e78923
Introduction Delirium: manifestation of encephalopathy • In delirium tremens, Wernicke encephalopathy and schizophrenia: temperature regulation is disturbed • Does delirium affect thermoregulation?
Aim of the study To investigate whether: • ICU delirium is related to absolute body temperature • ICU delirium is related to temperature variability
Methods • Subjects from 3 previous delirium studies • Daily delirium assessments by research- nurse/physician Temperature: measured per minute 24/7
Methods Inclusion: • Patients with delirious + non-delirious days during ICU admission of >24 hrs Exclusion criteria: • Disturbed body temperature regulation (treatment/diagnoses) • Neurological/neurosurgical disease • Days with sepsis, coma or death were excluded from analysis *Allpatients received paracetamol 1000 mg 4 times daily
Methods No Delirium Delirium Coma
Methods Linear Mixed models: • Univariable (unadjusted) • Multivariable (adjusted for confounders RASS and SOFA) Outcome: • body temperature [°C] • temperature variability (absolute second derivative) [°C/min2]
Results Body Temperature:
Results Temperature Variability:
Discussion Strengths: • Delirium diagnoses prospectively • Within subjects comparisons • Easy method temperature variability Limitations • Possible effect of medication • Natural circadian rhythm bias
Discussion Temperature variability: increased during delirium in ICU patients • encephalopathy that underlies delirium Future studies: • Monitoring temperature variability in total ICU population • Combine with EEG for objective tool to detect delirium
Delirium detection based on monitoring of blinks and eye movements Van der kooi et al. Am J Geriatr Psychiatry. 2014
Introduction Delirium associated with change in motor level activity • Actigraphy not practical • Eye movements less affected by muscle weakness, restraints, pain
Goal Determine whether eye blinks and eye movements differ in patients with delirium compared to patients without delirium.
Methods Population: post-cardiac surgery patients Reference: psychiatrist, geriatrist, neurologist using DSM 4 criteria
Methods Standard 21 electrode EEG recording (30 minutes) with periods of eyes open and closed First artifact free minute selected with eyes closed and open
Methods: Eye movements Eye movements compared between delirium and non-delirium Number (per min) and duration (sec) of: • Blinks • Vertical eye movements • Horizontal eye movements
Results: eye movements Eyes Open
Results: eye movements Eyes Closed
Conclusion Especially blinks are affected in delirious patients Strengths: • non-invasive • Only 1 minute of data necessary Limitations: • 22 electrodes needed for eye movement measurement, except for blinks • Difference in Apache and Charlson Comorbidity score Future studies: • Detection of eye movements in general population of ICU patients • Determining whether eye movements can detect delirium at early stage
Delirium detection using EEG: what and how to measure? Van der kooi et al. Chest. 2014
Introduction Delirium characterized by EEG abnormalities • EEG not practical Without Delirium With Delirium
Goal Determine the electrode derivation and EEG characteristic that have the best capability of discriminating delirium from non-delirium
Methods Standard 21 electrode EEG recording (30 minutes) with periods of eyes open and closed First artifact free minute selected with eyes closed
Methods: EEG Eyes closed= 210 different derivations
Methods: EEG For every derivation 6 parameters: 1 Relative delta power (0.5-4 Hz), Relative theta power (4-8 Hz),Relative alpha power (8-13 Hz), Relative beta power (13-20 Hz), Peak frequency, Slow-fast ratio δ 0-4 Hz θ 4-8 Hz α 8-13 Hz Ruwe EEG β 13-20 Hz 1van der Kooi, et al. J Neuropsychiatry Clin Neurosci 2012; 24: 472-477.
Methods: EEG 210 derivations x 6 parameters = 1260 combinations All 1260 combinations • Compared between delirium and non-delirium (Mann-whitney U) • P-values ranked • smallest p-value is optimal combination (Bonferoni correction ) 1van der Kooi, et al. J Neuropsychiatry Clin Neurosci 2012; 24: 472-477.
Results: EEG *p< 4.0*10-5 is significant
Results: EEG Most optimal electrode locations, based on first 4 rankings.
Conclusion EEG easily detects delirium from non-delirium using • 2 electrodes in frontal-parietal derivation and relative delta power Strengths: new approach, non-invasive, only 2 electrodes and 1 minute data necessary Future studies: • Validation study in unselected population of postoperative- and critically ill patients • Determine whether it recognizes delirium at an early stage
Overall Conclusion EEG most promising method for delirium detection. Project started: Development of delirium monitor
Product development Product and algorithm
Validation study Goal: To determine sensitivity, specificity and predictive values of the delirium monitor when compared to reference standard (specialized geriatric nurse) in elderly postoperative patients (n=154).
Usability study • Practical? • Easy to Use? • Opinion of nurses of different medical departments
Results: EEG eyes open *p< 5.6*10-4 is significant Delirium met/zonder haloperidol geen verschil (p=0.37)